Lake Jualbup

This page contains information about Lake Jualbup, including progress and updates on the project to maintain a permanent body of water in the lake, the Lake Jualbup Accord project and other significant information.

The city's Lake Jualbup project team meets on a regular basis in order to progress the council resolution of February 2012, which can be viewed in the minutes of that meeting. A key resolution was for council to build a constructed lake to maintain a sustainable but adequate permanent body of water in Lake Jualbup. The team is in contact with relevant agencies, who have requested in depth information about a variety of areas to enable them to consider the proposal. These include (but are not limited to) a hydrogeological investigation to manage water levels and aquatic fauna surveys.

A diagram of the plan approved by council in February 2012 can be viewed here:

A forum for the stakeholder groups involved in the Lake Jualbup Project was held at the city on Monday 4 August 2014. The aim of the forum was for the city to fully understand the requirements of the various agencies which hold authority over the site.

The main issues discussed at the forum centred around environmental impacts, infiltration and retardation of surface water, community consultation, heritage issues and potential issues in relation to site contamination. Stakeholders at the forum also identified that a site management plan needed to be developed in order to consider all risks and demonstrate that contingencies are in place for their mitigation.

At its August Ordinary Council meeting, Council endorsed:

The implementation of the outcomes of the stakeholder forum held on 4 August 2014 including the engagement of a suitable consultant to develop a management plan for the whole site known as Lake Jualbup, Shenton Park.

That the draft management plan be developed in consultation with the Lake Jualbup working group and statutory stakeholders.

That Council approve the Lake Jualbup working group's proposed investigation of alternative products in addition to the polymer treatment intended to reduce the infiltration of surface water through the lake bed.

The city is working through the above implementation plan in order to complete the endorsed plan for Lake Jualbup.

On 19 Junary 2016, the management plan was presented to Council and endorsed. It acknowledged the views of both the city and the Lake Jualbup working group who had collaborated in the development of the plan.

The city and the Lake Jualbup working group have been working in consultation to develop a management plan for Lake Jualbup, Shenton Park. The draft document is currently with key stakeholders and regulatory authorities for comment. The plan will be presented to council in February 2016.

Overall project update – 17 August 2015

Overall project update – 3 March 2015

Overall project update – 15 December 2014

Contaminated site investigation

The initial desktop contaminated site investigation by GHD was completed in October 2013 and the subsequent detailed site investigation concluded in July 2014. A copy of the final report was provided to the Department of Environmental Regulation (DER) for comment and they recommended a number of further investigations, which will occur during the financial year 2015/16.

Lake bed

As part of the review of the contaminated sites investigation, it was established that the soil properties at Lake Jualbup were likely to support the use of a polymer product. However, the provider of the polymer requires access to the lake bed to test the product suitability. The polymer trial has therefore been put on hold as the city does not have the necessary statutory approvals in place.

As per point three of Council’s August 2014 resolution, investigations into the use of bentonite clay have commenced. It is hoped that the use of a bentonite product will retard the horizontal leakage to the extent that water remains in the lake for longer.

North / north eastern wall

Concept drawings showing the proposed cut and fill activity required to create a sloping bank along the northern edge of the lake were developed by GHD and provided to the Water Corporation (WC) for comment. The WC endorsed the concept drawings following which GHD developed final construction drawings.

The construction drawings contain two options to retard the horizontal infiltration of storm water. The first option is to incorporate a layer of bentonite clay within the sloping bank and the second is to install a Geotextile Clay Fabric (GCF) blanket at depth within the sloping bank. The Water Corporation is currently reviewing the construction drawings but have yet to sign off on them.

Stakeholder consultation

In response to several meetings with the Department of Aboriginal Affairs, city staff met with representatives from South West Aboriginal Land and Sea Council (SWALSC) in order to inform them of the project and to arrange to present to the Whadjuk Working Party (WWP). This presentation to the WWP took place on Wednesday 10 December and feedback from the WWP is anticipated in the near future.

Management plan

The request for quote to develop a management plan for Lake Jualbup was advertised in The West Australian on Saturday 29 November 2014. It is anticipated that a consultant will be appointed in January 2015.

Rockwater Pty Ltd was engaged by the city in June 2012 to complete a study to determine the best approach for water management in the catchment to maintain an adequate body of water in Lake Jualbup. The draft hydrogeological investigation report was received by the city on 27 November 2012 and can be viewed below, together with a copy of the presentation of the report given by Rockwater on the same date to city staff and members of the community group Save Our Jewel.

The report was sent to the following agencies for comments on the results by 1 February 2013. A copy of the feedback from each agency can be found below. Based on the response from agencies and community members, the city has requested Rockwater incorporate the feedback to finalise the report.

North / north east wall removal and creation of sloping banks

Designs are currently being drawn up in order to remove the north / north east walls and create sloping banks as per the Council endorsed plan. When the drawings are complete, they will be provided to the Water Corporation for approval. Once the work has been approved, the city will request quotes and proceed with implementation.

Water Corporation – responsible for drainage and property protection from flooding

The Water Corporation is concerned the proposal may lead to increased risk of flooding for nearby residential properties, as the rate of overflow from the outlet drain may have been overestimated. It is noted that some of the data used is incorrect, and the models should be run with updated data to confirm the recommendations. In particular, the elevation of the outlet drain and calculation of the rate of discharge from the outlet drain needs to be updated. More detailed information on the polymer application and maintenance is also required.

The EPA requires an Environment Management Plan for Lake Jualbup to make a decision on the proposed management approach. The Environment Management Plan should take into account comments from all government agencies and results of the hydrogeological investigation and aquatic fauna survey. Specifically, the plan should detail appropriate management for the impacts on water quality, risk to aquatic fauna, and potential for disturbance of acid sulfate soils.

Department of Environment and Conservation (DEC) – responsible for advising on wetland ecology and protection

The DEC requires an Environment Management Plan for Lake Jualbup and recommends that the city retains Lake Jualbup's current hydrological regime. DEC does not support a permanent water body due to concerns about the impacts of a permanent waterbody on the ecosystem, specifically for aquatic macroinvertebrates, frogs, turtles and waterbirds. DEC recommends the plan should also detail treatment of drainage water entering the system, and the management of midges and mosquitoes.

Department of Water (DoW) – responsible for the management of Perth's surface and groundwater

The DoW recommends that the lake be maintained or upgraded without any lining of the lake bed, due to concerns about the potential to reduce natural infiltration and recharge of water into the superficial aquifer. Specifically, the Lake Jualbup proposal is anticipated to increase outflow from the lake to the ocean by three to four times, which is not supported by DoW. The DoW recommends that further investigation into the use of soakwells to recharge the local superficial, and the development of a management plan to address issues such as midges, mosquitoes, water quality, algal blooms, eutrophication and odour problems.

The DIA requires a risk assessment according to the 'Cultural Heritage Due Diligence Guidelines' to determine whether consent under the Aboriginal Heritage Act 1972 will be required for the proposed management of Lake Jualbup. It is currently not clear how the addition of a polymer and raising the drain outlet will impact on the Aboriginal heritage values.

Save Our Jewel

Save Our Jewel is a community group representing the views of local residents in Subiaco. Aerial photographs provided by Save Our Jewel of the anticipated normal view of Lake Jualbup after restoration in the summer and winter seasons can be viewed below.

The expression of interest (EOI) for the supply and application of water retaining polymers was advertised in the West Australian on Saturday 28 July 2012. A copy can be viewed below. The EOI has now closed and one submission was received.

A request for quotation (RFQ) was advertised in the West Australian on 1 September 2012. A copy can be viewed below. The aquatic fauna survey will provide current information on the oblong turtle population size, and species of waterbirds, frogs, fish, crustaceans and aquatic macroinvertebrates present at Lake Jualbup. The quotation was awarded to Wetland Research and Management. Fauna groups were monitored in spring 2012, with the second monitoring period completed in autumn 2013.

The project team has been advised by the Department of Aboriginal Affairs (DAA) (formerly DIA) to make a regulation 10 application in order to repair or replace the western and southern walls. A copy of this letter can be viewed below. The city is in the process of completing the application.

There is already approval in place for the northern wall to be removed, so designs are currently being drawn up and then a tender process will commence.

Permeability of lawn area surrounding the lake

The city commissioned Coffey Geotechnics to carry out an investigation to assess the soil parameters adjacent to the lake, particularly in relation to the infiltration capacity of the adjoining area during flood events. The focus of the investigation was to make an assessment of the hydraulic conductivity ( in-situ permeability) of the soil along the western end of the lake where the area is more susceptible to flooding during heavy rainfall events. Investigations were carried out at six locations around the lake and the results can be seen in the report below.

The city received a notification from the Department of Environment Regulation (formerly Department of Environment and Conservation) on 10 June 2013 advising that the site known as Lake Jualbup has been classified 'Possibly contaminated – further investigation required'. A consultant was engaged to conduct a preliminary site investigation which was completed in October 2013. A detailed site investigation of Lake Jualbup was completed in July 2014. Based on the results of the investigation, the Contaminated Sites Branch of the Department of Environment Regulation (DER) has determined that the classification of the site remains unchanged as 'Possibly contaminated - investigation required'. However, reasons for the classification have been updated and the city is continuing to work with the DER to finalise the classification. It may be that further site investigations are necessary. The results of the detailed site investigation can be viewed below.

In early 2012, the proposal to maintain a permanent body of water in Lake Jualbup was referred to the Environmental Protection Authority (EPA), an independent body that provides advice to the Western Australian Government on the protection of the environment. On 18 March 2013, the EPA notified the city of its decision that the proposal does not warrant formal assessment under the Environmental Protection Act 1986. While the proposal raises environmental issues regarding water quality, impact on aquatic fauna and potential for development of acid sulphate soils, the EPA considers that these can be adequately addressed through an Environmental Management Plan for Lake Jualbup. All correspondence relating to the EPA's decision can be viewed below:

The QEII Hospital redevelopment requires extraction, or ‘dewatering’, of groundwater during excavation works to allow building foundations and sub-surface infrastructure to be constructed. The extracted water is re-infiltrated into the ground via on-site recharge wells. Any excess flows into the hospital site lake and is pumped into Lake Jualbup through the stormwater system. The dewatering commenced in June 2012 and finished in February 2013.

No excess water was pumped into Lake Jualbup during the hospital redevelopment period, except for between October and November 2012. As a result, water levels at Lake Jualbup were higher than usual during spring. The city completed weekly recording of pump run hours to determine the volume of water directed into Lake Jualbup and the developer completed regular water quality monitoring of the extracted groundwater and Lake Jualbup.

In spring 2013, Lake Kilgour on Aberdare Road, Shenton Park, will be completely drained to allow access for earthworks. The objective of the earthworks is to increase the water holding capacity of the lake, which is used for irrigation of landscaped areas on the hospital grounds. The environmental value of Lake Kilgour will also be improved, with exotic wetland weed species removed and native vegetation planted. Works will also involve remediation of areas of contaminated soil. It is estimated that thirty to fifty long neck turtles are present in Lake Kilgour. DEC have provided a licence for translocation of the turtles to Lake Jualbup. Translocation will occur between July and August 2013. All turtles will be microchipped and monitored monthly until October 2013 to determine their health, condition and movement in their new environment.

The Lake Jualbup Accord project has now come to a close. Aha! Consulting has submitted its final report to the city, which was considered by council at its meeting on Tuesday 28 February 2012. The report provided an overview of the findings of the project's six focus areas and the associated options, and was based on four key pieces of information, including:

technical review by RPS on water options

a community survey

order of magnitude costings by Syrinx Environmental

Aboriginal heritage consultations.

Five reports relating to the above information are available for download below. The Aboriginal heritage report is confidential and is unable to be released due to provisions named in Section 7(1)(b) of the Aboriginal Heritage Act. The council decision can be found in the minutes of the meeting.

Community Reference Group (CRG)

The Lake Jualbup Accord project Community Reference Group (CRG) has disbanded. The CRG helped shape the survey process and questions, and played a key role in ensuring the process remained accountable to the community.